The Forth and Clyde Canal was closed as a navigable waterway in 1963. At this time, the average water level in the canal was lowered by around forty centimetres to make the canal easier and less costly to maintain. The words ‘THEN’ and ‘NOW’, carved opposite one another on facing canal walls, mark these two water levels and different phases in the canal’s ongoing evolution.

The words were carved by stone sculptor, David Wilson, who had to carry out the work standing on a platform partially submerged in the canal and wearing a drysuit. This was, he commented, ‘a first’ for him.

The letters are inscribed upside down and in reverse, so that they can only be read when reflected in the water. Wind rippling the canal’s surface or rain spotting the water blurs the reflections, meaning that the words are only clearly legible on still, dry days. Small fluctuations in the daily water level also mean that the word ‘NOW’, carved on the mean water line, is sometimes partly covered, taking on the appearance of an unidentifiable hieroglyphic.